The present invention relates to a vortex pump which is converted from a centrifugal pump; to an adjustable vortex pump; and to an adjustable impeller for a vortex pump.
By way of background, there are in existence centrifugal pumps which include a power frame and a casing containing a centrifugal impeller. Insofar as known, in the past such pumps were not converted to vortex type pumps, nor were the power frames and casings of centrifugal pumps utilized as parts of vortex pumps.
Insofar as known, prior vortex pumps usually mounted an impeller which was capable only of providing a particular discharge characteristic at a given speed. If a different discharge characteristic was desired from a particular pump, the speed of the pump had to be changed, thereby losing efficiency, or the impeller had to be replaced in its entirety.
Insofar as known, while centrifugal impellers of the type shown in U.S. Pat. No. 4,139,330 were adjustable by pivoting the vanes to different positions, it was not known to vary the characteristics of vortex type of impellers by repositioning each vane on a hub to provide different impeller diameters while limiting the range of the discharge angles of the vanes to a small predetermined value, nor was there any teaching in the prior art of selectively replacing vanes on a common hub with other vanes of a different size to vary the diameter of the impeller.